How to increase the speed of rendering
RAM is mostly about storage amount. More ram will allow you to render more complex &amp; more populated scenes (more objects, more polygons, more textures, etc....).

It will not have a significative impact on render times, unless you have less ram than is needed to handle the complexity of your scene (the more complex the scene the more ram is required) - in which case your system will store on your hard drives, which are way slower.

The important hardwares in render times are the CPU and the GPU.